ORA-00453: backgroud process 'MMON' is dead

1.Symptoms

When change db_recovery_file_dest_size parameter , following error encounter :

SQL> alter system set db_recovery_file_dest_size =5G;

ERROR at line 1:

2.Cause

During shutdown immediate operation,shutdown immediate hang and cancelled by user as archive log destination is full . However MMON process already shutted down by database .

MMON (Memory Monitor) is a background process that gathers memory
     statistics (snapshots) stores this information in the AWR (automatic
     workload repository). MMON is also responsible for issuing alerts for
    metrics that exceed their threshold.

3.Solution

1) Cleared the archive log destination (Make the space available in archive log destination), then PMON process automatically restarts the MMON process.

Or manually wake up pmon as following :

--Check pmon process id

select P.SPID,BG.NAME,P.PID,P.PNAME,P.PROGRAM ,DESCRIPTION from v$process p,v$bgprocess bg where p.addr=bg.paddr and bg.name IN('MMON','PMON','SMON');

--Wakeup pmon process

SQL> oradebug wakeup

2) If pmon wakeup mmon process failed , place system in restrict session would wake up mmon process .

--Check any active transaction in database before place database in restricted mode .

select status, taddr, count(*) from v$session group by status, taddr;

grant restricted session to public;

alter system enable restricted session;

alter system disable restricted session;

revoke restricted session from public ;

3.1. Note

In restricted session mode only the users with restricted session privilege can connect to database , other normal users cannot connect with database unless disable the restricted session mode.
Already Connected users can perform DML/DDL activities , but no new session will create for the users .